The contracting agency shall make the contribution for its employees in this system, as recommended by the actuary and approved by the board and certified by it to the contracting agency.
The contribution may consist of fixed sums, percentages of compensation of contract members, or both, and shall be paid to this system as provided in the contract.
The actual contribution is subject to adjustment by the board as may be necessary on account of any additional prior service credits that the contracting agency may desire to provide for its employees in this system or on account of experience under this system as determined by periodical investigation, valuation and determination required to be made by the board, including adjustments determined as necessary by the board, even after the total contributions determined, plus subsequent adjustments, if any, have been completely paid.